We have tested this experimental approach by using the SIV GAG protein as a model antigen. Recombinant GAG protein was prepared in the designated vector and the fusion protein obtained was mixed with Lactobacillus acidolphilus. Binding of the GAG protein to the bacteria was observed and mice were administered the microorganisms +/- the SIV GAG protein via stomach gavage over a 3 week period. A strong antibody response was observed in 2 of 4 treated mice after 2 or 3 weeks of immunization. Based on this positive response, we are developing recombinant tumor antigen fusion proteins, i.e. TARP and K-ras, in order to evaluate the host response to these antigens when presented on the surface of Lactobacillus. Upon creation of the appropriate recombinant we will determine if the mice can be protected from KRAS driven tumors. We have also found that additional low stimulation by LPS may be required to elicate a host immune response to the target antigen.